Quinalizarin is primarily used as a complexometric indicator in analytical chemistry. It is particularly effective in the determination of metal ions, such as aluminum, beryllium, and magnesium, due to its ability to form distinct color changes upon complexation. This property makes it valuable in titrimetric analysis for precise endpoint detection. Additionally, it finds application in histology as a staining agent for identifying specific cellular components, enhancing the visualization of tissue structures under microscopy. Its role in biochemical research includes studying enzyme interactions and metal ion binding in biological systems. Quinalizarin is also explored in material science for developing sensors and colorimetric assays, leveraging its chromogenic properties.